Microfouling inhibition of human nosocomial pathogen Pseudomonas aeruginosa using marine cyanobacteria

Pseudomonas aeruginosa is a Gram negative, opportunistic biofilm forming pathogenic bacterium which is developing as a serious problem worldwide. The pathogenicity of P. aeruginosa mainly depends upon biofilm and quorum sensing (QS) mechanism. Targeting biofilm and QS regulated factor will automatically reduce the pathogenicity of P. aeruginosa. Therefore it is compulsory to identify naturally derived biofilm and QS inhibitors against P. aeruginosa. In the present study Oscillatoria subuliformis, a marine cyanobacterium was used against the biofilm and QS of P. aeruginosa. O. subuliformis intracellular methanolic extract (OME) at different concentration (1.5 μg mL^-1, 3 μg mL^-1 and 5 μg mL^-1) was tested against several virulence factors like Extracellular Polymeric Substance (EPS), Cell Surface Hydrophobicity (CSH), elastase, pyocyanin and swarming motility. OME inhibited biofilm (56%), EPS (40%), CSH (56%), pyocyanin (27%), elastase activity and swarming motility in P. aeruginosa without interfering in their survival. Characterization of the OME using FTIR and GCMS confirmed palmitic acid and oleic acid as active compound. CLSM analysis of catheter coated with OME, palmitic and oleic acid proved biofilm inhibition over urinary catheters. The results postulates that oleic and palmitic acid could be an effective attenuator of P. aeruginosa pathogenesis.